Dynamite primer cartridge



Nov. 10, 1942. L. w. EARLY DYNAMITE PRIMER CARTRIDGE Filed ook. 12, 1939 2 Sheets-Sheet 1 INVENTOR LAWRENCE W. EARLY ATTORNEY Nov. 1o, 1942. w, EARLY' 2,301,384

DYNAMITE PRIMER CARTR IDGE Filed Oct. 12, 1959 Sheets-Sheath 2 LAwR'ENcl-z w. eALY INVENTQR We). aw- (8.

A'ITORN EY there prepare the primers.

Patented Nov. 10, 1942 DYNAMITE ranma CARTRIDGE Lawrence W. Early,

Hercules Powder Company,

Wilmington, Del., assignor to Wilmington, Del.,

a corporationvof Delaware vAlmlication OctoberlZ, 1939, Serial No. 299,161

(Cl. 1oz- 27) 4 Cflaims.

This invention relates to an improved explosive primer and more particularly to an improved explosive primer tube including a tube containing a firing device and of such size as to receive a cartridge of explosive.

As is well known, the established method of the art for iring explosive charges is by the use of blasting caps inserted into` one of the cartridges of the explosive that makes up the charge. Explosive charges so fired may be large or small and of any of the various commercial types such as, for example, straight or extra dynamites, gelatins, permissibles, or the like. The blasting cap used is either fired electrically or by a fuse and may be either of the instantaneous or delay type. This combination of a blasting cap in conjunction with a cartridge of dynamite is called a primer by the art.

In many operations the primers, described above, are made up at a point remote from the shooting face to provide an added degree of safety and to effect a saving in loading and iiring time. In other operations it is necessary, due to company rules, local laws, etc., to take the dynamite and caps to the shooting face separately and This type of operation consumes time and under many conditions is considerably more dangerous than the use of prepared primers.

It is the object of this invention to produce an improved primer. A further object of the invention is to produce a primer tube in which is positioned a ring device. A still further object of this invention is to prepare a primer tube of suicient size to allow the insertion of an explosive cartridge. A still fu'rther object of this invention is to produce a primer tube that facilitates the quick preparation of an explosive primer. Other objects will appear hereinafter.

The objects of this invention may be accomplished by producing a tube of such size in relation to diameter and length that a particular explosive cartridge may be easily but snugly inserted therein. The primer tube, in general, may include a rigid outside member and an inside member which conforms to and holds a blasting cap securely against the inside surface of the outside member. The blasting cap is therefore positioned securely between two layers of material and will further, upon the insertion of a dynamite cartridge be in close contact with the dynamite. To provide more positive contact of the detonating part of the blasting cap with the inserted dynamite cartridge the inside member is of the cap is exposed to the dynamite cartridge. Alternately, the outside tube may be slotted and the blasting cap threaded therethrough to effect the positioning instead of using two layers of material. Thus, the cap is positioned without the use of an inside member.

Having now indicated in a general way the nature and purpose of this invention, there follows a more detailed description of preferred embodiments thereof, with reference to the accompanying drawings in which like numerals refer to similar parts of the drawings.

Figure 1 is a cross-sectional view of the primer tube with a delay electric blasting cap fastened securely in position. Figure 2 is an end view of Figure 1. Figure 3 is an elevation view of the primer tube with a delay electric blasting cap in position and with the leg wires of the cap packaged within the tube'. Figure 4 is a crosssectional view along line 4-4 of Figure 3. Figure 5 is an elevation view of a primer tube with a delay electric blasting cap in position and a dynamite cartridge inserted within the tube. Figure 6 is a cross-sectional view along line G-B of Figure 5. Figure 'I is a cross-sectional view of a primer tube with a delay electric blasting cap threaded therethrough. Figure 8 is an end view of Figure 7. Figure 9 is a side elevation View of a primer tube with a delay electric blasting cap threaded therethrough and with a label thereon, a part of the label being removed to show the portion of the primer tube with the blasting cap therein. Figure 10 is an end view of Figure 9.

To facilitate a clear description of this invention, the primer tube will be described without a dynamite cartridge inserted therein such as is shown in Figures 1 and 2. In Figures 1 and 2 the primer tube l includes an outside tube 2 of paper, cardboard, plastic, or fiber construction and iitted inside this tube 2 there is a similar second or inside tube 3 so constructed and shaped. as to fit snugly therein and to provide a tubular recess 4 into which an electric blasting cap 5 may be inserted. It will be noted that the inside tube is so formed at point 6 as to allow exposure of the detonating section 1 of the blasting cap 5. Thus, this exposed section 'l of the blasting cap 5 will, upon insertion of a dynamite cartridge, be in close contact with the dynamite and will insure positive detonation of the entire explosive charge. The blasting cap 5 may be held in place by pouring a sulfur plug 8 around its upper section as indicated. To reduce the possible obstruction that the inside tube 3 may offer to the insertion of' a `cut in such a manner that the detonating part '.55: dynamite cartridge, the end has been tapered as shown. Such a taper may best be visualized by passing a vertical plane downwardly through the tubular member at an angle to the longitudinal axis thereof, the line of intersection between the plane and the tubular member providing the taper desired. In the event the tubular member is made'frqm a at rectangular piece of material adjacent corners of said pieces of material adja- 'cent one end thereof may be` beveled inwardly.l When such material is formed into a tube, the

desired tapered end will be provided. It will be evident, of course, that all portions oi the outer surface of this tube will fit snugly within the outside tube. When a cartridge is inserted into the assembled primer, it will encounter the tapered portion of the inside tube and can be quite readily pushed past said tapered portion. In the event no taper is provided an inserted cartridge will abut a continuous ridge formed by the end of the inside tube, suchridge oiering considerably :more resistance to continued inward movement of the cartridge than would the tapered tube. It will be VVVunderstood that this inside tube 3 may also be the same length as the outside tube 2, as in Figure or may be cut shorter, as in Figure 3, the design of the said tube merely facilitating the eidcient retention of the blasting cap in its proper place and aiding in allowing the easy insertion of the dynamite cartridge into the assembled primer tube.

In Figures 3 and 4 there is shown a modication of this invention which includes a convenient accises posed to the outside at points i3. In all cases the detonating end oi the ring device will be positioned so that it may contact the explosive cartridge. In some cases it may be necessary to cut away a portion of the tube to expose the detn -onating end of the firing device to contact with the explosive cartridge. To hold this .tiring device in position, glue or other adhesives may be used between the tube and the ring device. It will be apparent that the wires of the cap in this embodiment may be packaged in the ways described hereinbefore.

In Figures 9 and 10 an additional variation of this invention is shown. Thus, the primer tube i includes an outside tube 2 through the wall of which the ring device is threaded. This threading procedure is described with reference to Figure 7. The tube 2 after the iiring device 5 is in position is wrapped with a label Hl which may entirely cover the' outside of the tube 2 although it should be appreciatedthat in some instances it means oi packaging the leg wire 9 of the electric blasting cap 5 for shipment of the primer tubes. Thus, the primer tube i similar to the tube shown in Figure 1 includes an outside tube 2 and inside tube 3, placed to holdan electric delay blasting cap 5 in position. The leg wires Q of the cap 5 are folded in the conventional accordion fold and the bundle inserted 'within the primer tube i. The ieg wires 9 may, i desired, be tagged to indicate the delay period of the delay blasting cap 5 used in the device, or the delay period may be printed on the outside oi' the primer tube itself. The length of the leg wires t and the size oir the primer tube i will, of course, effect the method of packaging but such adjustments are, as will be apparent, contemplated. Thus, for example, ii the lead wires are too long and/or too bulkv to be packaged inside the tube i they may be packaged on the exterior oi the tube in any suitable manner.

Figures 5 and 6 indicate how the primer tube i of this invention is to be combined with a dynamite cartridge lil to quickly effect 'the construction of a primer ready forl use in any explosive operation. Thus,- the bundled leg-wires Q, shown in `Figure 3, are removed from the inside of the tube l and a dynamite cartridge l@ is inserted into the tube l. The size of the tube l and the size of the dynamite cartridge it are coordinated so that the cartridge ill is easily slipped into the tube i but in such a manner that a snug t is maintained and close contact is produced between the dynamite cartridge and the detonating section 'i of the blasting cap In Figures '7 and 8 there is shown a modification of this invention which discloses a means of joining the :tiring device to the tube without the need of using a tube of double thickness. Thus, the primer tube i includes only an outside tube 2 and the electric blasting cap 5 is inserted through the wall of this tube 2 with a threading motion. The

tube 2 is slotted at points ii and the ring device is enclosed within the tube at points l2 and QX- may be desirable to cover only that portion of the tube in which the ring device 5 is positioned. The label M snugly engages the outer surface of the tube including the portions l2 which embrace the outer portions of the ring device, and thus aids in re-eniorcing the primer tube vand in retaining the firing device in position. The label may also cover the detonating end of the firing device if the threading opertion leaves it exposed.

In these Figures 9 and 10 the tube is also shown to contain a split l5 along its longitudinal axis. This splitting of the tube allows the tube to be used with explosive cartridges of various diameters and in no way effects the priming efficiency. The split tube-will maintain its position about the explosive cartridge in a positive manner and gives results equal to the tubes without the split. Thus it is possible to place a. primer tube having, for

example a diameter of l inch on explosive cartridges having diameters from 1 to 2 inches. This expedient aids operations by reducing the dierent size tubes which must be stocked. It will be obvious that the label may, if desired, cover the longitudinal split. This tube may be used with larger diameter cartridges by simply tearing or breaking the label to allow opening the tube to receive the cartridge.

The primer tube of this invention may be made from a variety of materials suchas, for example, paper, cardboard, plastics, ber, or similar materials which may be shaped in the form of a tube. I have found that the preferable embodiment of my invention includes a tube prepared from 2 ply .016" testl liner paper as such material is sumciently rigid to withstand the necessary abuse and is also economically feasible. it will be apparent that if I use a ilber or plastic, the tube may be so molded as to have a recess for the blasting cap or I may use an inside sleeve of the same material or any other convenient material to retain the blasting cap in position. Also, the inside tube may be formed from fiat stock and shaped to the design wanted, inserted into the tube, and glued or otherwise fastened into place. This inside tube may be designed to expose the detonating section of the blasting cap as described hereinbefore or may cover the entire cap, the detonation of the dynamite being eiected through the cap covering. If the tube is to be of single thick- 'where it is necessary In the foregoing description, the blasting cap used in the primer tube of this invention has been of the delay type, but it is to be understood that there may be used any of the `various commercial 'electric firing devices such as, for example, delay so that a close iit is obtained between the two K I also contemplate cutting sufficient material from the inside tube to provide the proper fit between the inside and outside tube. This may-be accomplished by cutting and removing a longitudinal section of material from the peripheral portion of the inside tube. Thus, just sumcient material is removed to permit a close fit between the inner and outer tubes with the ends of the cut portion in abutting relation. Further, this inside tube may be, as described hereinbefore, manufactured from fiat stock and formed and placed inside the outside tube. Any such deviations of construction will be apparent to those skilled in the art and are understood to be within the scope of this invention, I have found that it is very desirable to fasten the two tubes together tubes.

. by any convenient means, the preferable means being to glue the two sections together. The use of the blasting cap threaded through a single thickness tube does away with the trouble of joining the double tubes described above. It may be desirable in some cases as a further aid in holding the entire assembly together, and also to aid in the waterproofness of the device, to dip the prepared tubes into molten parailin, rosin-parafiln, and mixtures of similar materials, either before or after assembly.

In order to positively position the blasting cap in its recess, a small amount of material such as, for example, glue, rosin, plastic, or molten sulfur may be poured into the tubular recess and allowed to harden. It will be obvious that when cutting the tube to provide unrestricted contact between the section of the blasting cap containing the detonating charge and the dynamite cartridge, the type of blasting cap to be used, especially as to length, must b'e considered. To accomplish the same result, the inside tube may be definitely placed so that the explosive end of the cap will at all times be in one position and thereby allow the non-explosive part of the cap to vary in position.

Since the primer tubes of this invention require the insertion of a dynamite cartridge before they are ready for loading, they are more useful to prepare primers quickly as, for example, at a tunnel face. The insertion of a dynamite cartridge in the primer tube of this invention is obviously a much simpler and easier means of preparing primers than the method of making a hole in the dynamite cartridge, inserting a blasting cap therein. and taking the necessary precaution to prevent the cap from being pulled out of the cartridge during the bore hole loading operations.

The advantage of myimproved primer in tunnel work is of major importance as in some districts blasting caps and dynamite are not permitted to be transported into the tunnel together. This ruling precludes the possibility of transporting to a tunnel face the normal blasting .cap-dynamite cartridge primers.

cartridge. known to the art by the term primer and which is used in this sense in the present specication and claims.

Therefore, it is necessary for operators to carry blasting caps to the face of a tunnel then bring dynamite to the face and prepare the blasting This operation is time-consuming and dangerous. The use of the primer tubes of this invention alleviates this condition due to the ease, quickness and simplicity of preparing primers from the primer tubes of this invention. Further, it requires less skill to prepare and use the device of this invention than regular primers.'

Although my primer tubes are especially advantageous in tunnel work, their use will also be found advantageous in anyn explosive work whereY the necessity of preparing primers from a blasting cap and cartridge of dynamite is a prerequisite to blasting.

The primers prepared from the primer tubes of this invention may be used in exactly the same manner that a primer made by inserting blasting capV into a dynamite cartridge; therefore, my primers may be substituted in any explosive work and their attendant advantages of ease, quickness, and simplicity of assembly enjoyed.

It will be understood that the details and examples given hereinbefore are illustrative only, and in no way limiting on my invention es broadly described hereinbefore and in the appended claims.

What I Patent is:

1. A priming device adapted to receive and prime an explosive cartridge comprising an outer paper tube, an inner paper tube snugly fitted within the outer paper tube, said inner paper tube being provided with an inwardly extending portion forming a tubular recess, said recess extending longitudinally of the inner tube, a firing device positioned in said recess and securely fastened therein, said ring device having a detonating end extending from the recess into the interior of the inner tube whereby when an explosive cartridge is inserted into the inner paper tube the detonating end of the firing device will be in priming contact with the cartridge.

2. A priming device adapted to receive and prime an explosive cartridge comprising an outer tubular member, an inner tubular member snugly fitted within the outer tubular member, a longitudinally extending recess in said inner tubular member consisting of an inwardly pressed portion of the peripheral surface of said member, the inner end of said inner member being tapered to facilitate entrance of a blasting cartridge into the device, an electric ring device positioned in said recess and held therein by the outer tubular member, said firing device having a detonating end projecting from the recess into the interior of the inner tubular member, whereby when an explosive cartridge is inserted into the primer the detonating end of the firing device will be in priming contact with the cartridge.

3. A priming device adapted to receive and prime an explosive cartridge comprising a shockresistant tubular member, said member having a series of transverse cuts dividing a longitudinally extending portion of the surface of said member into a plurality of relatively movable sections, an electric firing device threaded through said sections so that one section passes above the firing device and the adjacent section below it, said ring device having a detonating end extending into cap-dynamite claim and desire to protect by Letters 'Patent No., 2,50l,58b.

extending portion of the surface of the tubular 10 member into a plurality of relatively movable strips., an electric ring device threaded through said strips in a manner such that one series of alternate strips pass under the Atiring device and another series of alternate strips pass over the firing device, said ring device having a detonat-y ing end projecting into the tubular member and a label wrapped around said tubular member and firing device and aidingfin holding them. in assembled position.

' MW'RENCE W. EARLY.

CERTIFICATE 0F CORRECTION.

November lO, 19b,2

LAWREN CE vW. v EARLY.

it is hereby certifiedthat error appears ,'n the printed specification the said Letters Paten of the above numbered patent requiring correction as follows; Page 5, second column, line 58, claim 2, before 7de-vice insert prmer and that t should be read with this correction therein that the same mayvconform to the record of the case in the Patent Office.

Signed andsealed this 29th day of'December, A D. l9L2.

.. (Seal) Henry Van Arsdale.,

Acting Commissioner of Patents.

CERTIFICATE OF CORRECTI ON rat-ent No. 2,501,58h. Noember 1o, 19m.

LAWRENCE W. EARLY.

It is hereby certifiedthst error appearsin the printed specification ofthe a`bove numbered patent requiring correction as follows: Page 5, secvons Column, lime '58, claim 2, before "device" insert A prmern and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed, this 29th day of- December, A. D. 19m.

Henry Van Ars dale,

,. (Seal) Acting Commissioner of Patents. 

